I gathered my courage at the end and asked if it's AI and it said yes, but I have no real way of verification. For all I know, it's a human that went along with the joke!
EDIT: I'm almost tempted to go back and respond to that email now. Just out of curiosity, to see how soon I'll see a human.
As a general rule I always do these talks with camera on; more reason to start doing it now if you're not. But I'm sure even that will eventually (sooner rather than later) be spoofed by AI as well.
What an awful time.